Improvement in speaking-telephones



J. H. IRWIN. Speaking-Telephones.

' No. 206,241. Pa'tented July 23,1878..

UNITED STATES PATENT OEEIoE.

.IonN n. IRWIN, on ruILA'IiIiLrIILn,frnnnsvnvnnin.

IMPROVEMENT IN SPEAKING-TELEPHONES.

Spcclicai ionformng pari of Leiters Fatont N0. 206,241, dated .Tnly 23, 1h78; 'npplicalion filed June 12,1878. y

To all rwho-m it muy. concern:

Be it known thatl, JonN II. IRWIN, of Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented new and useful Improvements in Acoustic Telegraphy, and that the following'is a full and complete specification of the same.

This invention relates especially to that branch'of acoustic telegraphy which pertains to the transmission' of articulate speech; and consists in anew method of controlling the electrical current and setting up therein of a series of undulations or periods of varyin g intensity corresponding to the sound-waves pro-.

ties or producing essentially different results. j

In all telephones capable of transmitting the sounds of articulate speech, sofar' as I am aware, the electrical undulations are controlled by the varying excitement produced by a diaphragm, disl1,'or plate vibrating in the immediate vicinity of a permanent magnet, or by the variable resistance of a conducting medium under strain.

In my receiver no magnet is present, and the electrical undulations are controlled directly by variations of resistance at an attenuated place in the line-Wire, the effect of vibration at or near that point. Therefore my discovery is that the peculiar vibrations produced by articulate sounds may be transformed into corresponding undulations of an electrical current by lthe interposition in the circuitcouduetor of two needles or pencils with their pointed ends in contact, as hereinafter set forth, and that the uudulatious so producedl may be transformed into articulatesouuds again by aVl proper instrument. IIence the apparatus ofthe ordinary electric lamp with its carbon pencils may, if properly adjusted .andconnected with a proper reproduccr, constitute a practical telephone.

Ila-ving pointcd1 out the general' feature of my improvement, I will more particularly describe the method in which I have appliedthe same',without, however, proposing to limit myself to the details shown or hereinafter particularlydescribed,having reference to the accompanying drawin gs, Vwherein-- Figure l' is a perspective sketch, showing my apparatus iu operative condition. Fi `2 isa perspective view of my transmitter detached. Fig. 3 is a vertical longitudinal section of the same. Fig. 4 is au enlarged sectional elevation the resisting point of attenuation. 'Vhen they recede from each other the circuit will be broken and all effect will cease.

To eifeet the proper adjustment suitable mechanism is required.

The undulations icapable of reproducing audible sounds in articulate form require an exceedingly delicate adjustment of resistance, au adjustment corresponding to the delicate vibrations in a sonorous body responding to sound-waves. This delicate,adjustment is eas ily obtained, while the the attenuated points e f are brought *into contact with a certain pressure, to be determined by' experimental adjustment of each instrument.

TheV pointed wires are thereforeset in `sub stantially rigid bases, one or both of which should be capable of sonorous vibration. Such a base is the plate g, which is rigidly mounted upon the post It and supported upon the base i. The vibration of the-plate f/ is sonorous, and it isto be understood that the distinction between the sonorous vibration of a rigid body is alone herein referred to in contradistinction to that species of vibration which characterizes a membranous or thin metallic diaphragm.

The needle c is rigidly attached to the plate g, and the needlef is attached to an adjnst' to vibrate, and the pressure of contact between able piston, 7:, which screws into the socket m., and may be. adjusted therein at will by means ot' the worin-pinion n and tan gent-screw p.

q and 1' are common-binding-screws for attachment of the line-wire B.

The proper attachments having been made, words are spoken in the immediate vicinity of the plate g, and said plate is thereby caused said points being,` in contact and subjected to a certain degree of pressure, as set forth,co1n bined with a battery, A, and rcproducer E, as set forth.

` 2. The rigid sonorous plate g, supported by va post, 71, and provided with the pointed wire c,

combined with the pointed wire f, adjustable in the solid base fi, for the purpose set forth.

3. The ri gid sonorous plate g, supported upon the post h, and the wires c j', pointed at their'ends, combined with the piston l', screwed into the socket m, and the worm-pinion u and tangent-screw p, substantially as and for the purpose set forth.

4. The attenuated points e f, set in substantially rigid bases and interposed in the line of a conductor, for the purpose set forth, coinbined with mechanism whereby the required adjustment of said points may be secured at will. c

J OI-IN II IRWIN. Witnesses:

(1r-ms: l?. 1l. llnuennno'm, WiLLrAM L. Yonmmn. 

